Dental shell



G. L. VAN ALLEN.

DENTAL SHELL.

APPLIQATION FILED SEPT. 21, 1918.

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Patented May 24, 1921.

' UNITED STATES PATENT OFFICE.

GIDBGE L. VAN ALLEN, Oi! PRINCE BAY, NEW YORK, ASSIGNOR TO BAKEB'& OOH- PANY, INC., A CORPORATION OF NEW JERSEY.-

DENIAL SHELL.

Specification of Letters Patent.

Application filed September 21, 1918. Serial No. 255,068.

To all whom it may concern:

Be it known that I, GEORGE L. VANALLEN, a citizen of the United States, and a resident of Prince Bay, Staten Island, New York, have invented new and useful Improvements in Dental Shells, of which the following is a specification.

The objects of the invention are to secure in dental shells for crowning teeth an exterior or exposed surface of the desired hardness and color and yet have the article as a whole more workable or malleable than would be possible if it were entirely of a composition having that hardness and color; to thus enable the shell or other piece to be more readily and perfectly fitted to the tooth orshaped to the surface of the mouth; to this .end to use upon the unexposed interior of the article a softer metal or alloy, where the color is immaterial; to at the same time pre serve the essential and valuable qualities of the stock, such as its proper color where exosed, the resistance to tarnishing and so orth; to secure such stock which can be readily and conveniently manufactured, and

,to obtain other advantages and results as may be brought out in the following descrlption.

Referring to the accompanying drawings, in which like numerals of reference indicate the same parts throughout the several views.

Figure 1 is a perspective view of ashell of my improved construction; 7

Fig. 2 is a central longitudinal section of the same on enlarged scale to show the invention more clearly;

Fig. 3 is a similar section of a modified form of the invention;

Fig. 4 is a similar section of a further modification, and

Fi 5 illustrates a iece of bridge-work backlng on an enlarge scale.

In carrying out my invention, I form a sheet or plate composed of opposite outer layers of gold as commonly employed for this class of work, that is, of 22 carat gold,

' which is an alloy of gold, silver and copper,

and of the dark shade and degree'of hardness desired by dentists. Between these two outside layers, however, I employ a middle layer of softer material such as silver or silver and gold, the thickness of this middle layer being referably considerably greater than that of the outside layers or equal to both of them. All these layers are welded or sweated together by any suitable process,

so that they are held firmly together and is much softer or more malleable than if it were all of the same composition as its sides, and thus it can be more readily shaped to conform to a toothor to the interior of the mouth. For instance, the shell 1 shown in Figs. 1 and 2 of the drawing can be very readily pressed or shaped to conform to the appearance of a natural tooth and yet when thisis done it will look the same as if it were entirely of hard gold and will resist the wear upon it. Obviously the same results and advantages will be secured in all kinds of dental stock which can be made in a similar way, such as backings for bridge-work, plates, and so forth.

In said Figs. 1 and 2, the reference numerals 2 and 3 indicate the hard outer and inner la ers of dark shade, respectively and 4 the so ter middle layer containing no copper and of a lighter shade than the layers 2 and 3. Obviously, while the entire wall of the shell must be substantially of the usual or standard thickness, the proportion of the different layers to each other can be varied somewhat.

In some kinds of dental stock, where onl one surface is ever exposed, as in a shell, may omit the interior layer similar to the exterior layer and make theshell simply of two layers, as shown in Fig. 3. Here 6 indicates an outer layer of the usual dark shade For bridge-work backings,shown in Fig.

5, the two outer layers 11, 12 are about one thousandth of an inch thickness each and the inner layer 13about two thousandths, and this secures a further advantage in that the middle layer being of lighter shade, or white if pure silver is employed, the cut edge of the sheet is lightened in color, and inasmuch as this shows at the biting edges of the teeth it will be more nearly the color of the teeth and hence not so conspicuous as the usual darker shade.

All kinds of dental stock which can be made of the construction described come within the scope of my invention, and I do not wish to be understood as limiting myself except as required by the following claims when construed in the light of the prior art.

Having thus described the invention, what I claim is:

1. A dental shell having one end closed layer and the inner layer being soft enough" so that the stock is more malleable than it would be if like the outer layer for its entire thickness.

2. A dental shellwith one end closed and side portions having for the entire circumference of the shell a middle layer and other layers on opposite sides of said middle layer which other layers are harder than said middle layer, the middle layer being soft enough so that the stock ismore malleable than it would be if like the opposite layers for its entire thickness.

3. A dental shell having one end closed and being composed throughout said end ing throughout said end and its side portlons amiddle layer and other layers on opposite sides of said middle layer which other layers are harder than said middle layer, the middle layer being soft enough so that the stock is more malleable than it would be if like the opposite layers for its entire thickness.

GEORGE L. VAN ALLEN. 

